Abstract
Dual-task walking may lead to gait instability and a higher fall risk in older adults, particularly when walking in a busy city street. Challenging street features such as narrow sidewalks not only discourage walking, but are also likely to be taxing for older adults' cognitive resources and gait characteristics. The aim of this study was to assess the way older adults' gait characteristics are affected by walking on a narrow path while performing a challenging cognitive task in lab conditions imitating common urban environments. Nineteen young and eighteen older adults walked on a narrow (40cm) and a wide (80cm) path and performed a cognitive (n-back) task individually adjusted to 80% accuracy. The two tasks were performed separately (Single-Task) and concurrently (Dual-Task). Both groups walked faster, and their step width was narrower on the narrow path. During dual-task walking on the narrow path, older adults showed significant dual-task costs in the cognitive task, gait speed, step width, and stride length. Dual-task walking was associated with decreased gait speed and stride length in both age groups, suggesting that dual-task walking may adversely affect gait, particularly when walking on narrow paths. These conditions may lead to gait instability and an increased fall risk for older adults, particularly when walking along the narrow sidewalks commonly found within the built environment. However, more research is needed in an urban setting to determine the extent of the fall risk narrow sidewalks present for older adults.